/Engine/Source/Runtime/Core/Public/Containers/RingBuffer.h
Add a new element after the back pointer of the RingBuffer, resizing if necessary. The new element is move constructed from the argument. Returns the index of the added element.
[IndexType](API\Runtime\Core\Containers\TRingBuffer\IndexType) Add ( [ElementType](API\Runtime\Core\Containers\TRingBuffer\ElementType) && Element )